using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using UnityEngine;

public class Server : MonoBehaviour {

    [SerializeField] int port;


    List<ServerClient> clients;
    List<ServerClient> disconnectList;

    TcpListener server;
    bool serverStarted;

    private void Start()
    {
        clients = new List<ServerClient>();
        disconnectList = new List<ServerClient>();

        try
        {
            server = new TcpListener(IPAddress.Any, port);
            server.Start();

            StartListening();
            serverStarted = true;
            Debug.Log("Server has been started on port " + port);
        }
        catch(System.Exception e)
        {
            Debug.Log("socekt error: " + e.Message);
        }
    }

    private void Update()
    {
        if(!serverStarted)
        {
            return;
        }

        foreach (ServerClient client in clients)
        {
            //is the client still connected
            if(!IsConnected(client.tcp))
            {
                client.tcp.Close();
                disconnectList.Add(client);
                continue;
            }
            //check for message form the client
            else
            {
                NetworkStream networkStream = client.tcp.GetStream();
                if(networkStream.DataAvailable)
                {
                    StreamReader reader = new StreamReader(networkStream, true);
                    string data = reader.ReadLine();

                    if(data !=null)
                    {
                        OnIncomingData(client, data);
                    }
                }
            }
        }
    }

    void OnIncomingData(ServerClient client, string data)
    {
        Debug.Log(client.clientName + "has sent the following message: " + data);

    }

    bool IsConnected(TcpClient client)
    {
        try
        {
            if(client !=null && client.Client != null && client.Client.Connected)
            {                	
                //true if Listen has been called and a connection is pending;
                if (client.Client.Poll(0,SelectMode.SelectRead) )
                {
                    return !(client.Client.Receive(new byte[1], SocketFlags.Peek) == 0);
                }
                return true;
            }
            else
            {
                return false;
            }
        }
        catch
        {
            return false;
        }
    }

    void StartListening()
    {
        server.BeginAcceptTcpClient(AcceptTcpClient, server);
    }

    void AcceptTcpClient(IAsyncResult asyncResult)
    {
        TcpListener listener = (TcpListener)asyncResult.AsyncState;
        clients.Add(new ServerClient(listener.EndAcceptTcpClient(asyncResult)));
        StartListening();

        //send a message to everyone, say someone has connected
    }

}

public class ServerClient
{
    public TcpClient tcp;
    public string clientName;

    public ServerClient(TcpClient clientSocket)
    {
        clientName = "Guest";
        tcp = clientSocket;
    }
}